Most crude edible fatty oils—of vegetable or animal origin—contain impurities which must be removed before the oil is suitable for consumption. Also fatty oils for technical use often have to be purified to some extent to make them suitable for their purpose.
The removing of impurities could be carried out by a degumming and/or winterization process and may be combined into one process a so-called cold degumming process. However, the traditional cold degumming process is not always successful because:                The separation efficiency is relatively low because of the increased gum viscosity at low temperatures;        The wax crystallization and the crystal growth are, to some extent, inhibited by the presence of gums.        